Here are all of the medals

Medals Awards What to do

Gunslinger-Precision-6 Kils with Pistol

Frenzy-Elite Assault Rifle-12 Kills with Blaster Rifle

Demolition-Guidable Rockets-4 Critical Hits vs. Vehicles

Technician-Vehicle Regen-Slice into a Vehicle

Marksman-Particle Beam Rifle-6 Headshots with Sniper Rifle

Regulator-Flechette Shotgun- 8 Kills with Shotgun

Endurance-Energy Recuperation-8 Points

Guardian- Shielding-16 Points

War Hero-Damage Increase-24 Points